View Full Version : What to do? Fuell E27 in Brazil

10-05-2016, 03:33 PM
Hi Buellers,
Come on ... I live in Brazil in Sao Paulo. Here we have a climate where 70% of the year has temperatures above 25 Celsius (77 fahrenheit). Regular gasoline has 27% ethanol and premium gasoline is 25% ethanol and according to Petrobras has 95 octane. I believe that regular gasoline also has 95 octane because of the large amount of ethanol. Taking all this into consideration, I would like to know the recommendation of you to have an engine running rounder. As you know, it has a compression ratio of 10: 1 (recommended for use petrol) and the manual tells you to use gasoline with 91 octane. And to not use gasoline containing more than 10% alcohol. The original map AFR varies between 14.7 (low) to 13 (high). These proportions are to use gasoline with 91 octane. The stoichiometric ratio of AFR for ethanol would be 9,8 correct. But as our gasoline has 27% ethanol, there must be a middle ground to get the best proportion. I have heard also that the O2 sensor original narrowband can not identify this amount of ethanol, hindering the correct reading. I not believe this information, since the O2 sensor le only the oxygen in the exhaust coming out, regardless of the fuel. What you guys advise?
Slightly change the compression rate to use our gasoline? Perhaps change the compression ratio, eg to 10.5: 1 or 11.0: 1 to suit a bit Brazilian gasoline?
Also decrease the AFR values ​​for a middle ground between the ideal for gasoline is 14.7: 1 for petrol and 9.8: 1 for ethanol?

What is the opnion of you? Thanks.

10-05-2016, 04:23 PM
Ethanol is not alcohol.
Ethanol does have a better octane rating (like alcohol) than gasoline.
My understanding of the Brazilian gas problem is that the quality of gasoline is very poor. Not that Ethanol is the issue.
These bikes were built late enough ('03-up) that you won't have issues with rubber degradation, but never let it sit with Ethanol in the tank. Ever.

10-05-2016, 05:22 PM
IIRC Gloomshadow (I think) had some posts with someone from South America on this issue. Search function of the forum is your friend.

10-05-2016, 06:37 PM
Thanks mrlogix. I will look.

Cooter... I do not know about the alcohol, but the ethanol sold in Brazil has 108 octane and E85 sold in some countries has 105 octanes.

http://www.unitedpetroleum.com.au/united/fuel/ethanol-85: "Flex Fuel vehicles are specifically designed to take advantage of the very high octane rating of 105, present in E85."

And E100 have 113 octanes: http://ethanolrfa.org/issues/ethanol-engines/

10-05-2016, 08:59 PM
Octane rating doesn't make any more power. It is simply a measure of it's resistance to pre-ignition. High octane gas actually burns slower than low octane gas.
Be aware there are 2 types of octane ratings. Here in the US, we typically average them. I don't know what other countries do.

If you question is meant to ask if you can make a ton more power by running the ragged edge of higher compression and timing because you happen to have 27% Ethanol at the pump?

I wouldn't.

10-06-2016, 08:30 PM
Actually Ethanol is alcohol (grain alcohol just like you drink) and does have a high octane rating. Methanol the kind used in drag race cars mostly is a lot harder on rubber parts. If I lived in brazil and had access to E85 or even pure Ethanol i would get a wideband setup on it and some bigger injectors and use the alcohol. It will make your bike run cooler also. This has been done by a few guys from Sioux Falls South Dakota on Harley's and they run great with no problems. If you want significant horsepower gains from the alcohol you will need to up the compression and advance the timing curve. Quit a bit of work and you will have to learn about tuning.

10-06-2016, 10:56 PM
Yes, technically Ethanol and Methanol are types of alcohol, and both are used in drag racing but the difference is bigger than universally using "alcohol" as I believe the OP was referring to.
NO you should not drink straight Ethanol or Methanol. It is NOT the same as grain alcohol.
Although your bike would run on pure grain alcohol (sort of), don't go pouring Everclear in your tank quite yet. There's a lot more to gasoline than octane rating.
Ethanol is well documented to be hard on rubber parts, just like Methanol and for the exact same reasons.
Yes, you can specifically build an internal combustion engine to run on Ethanol, Methanol, gasoline, Propane, Natural gas, even french fry oil...
I don't know where you live OnidaSTT, but if it's in the states you do have lots of easy and cheap access to E85 and E100. The HP gains from only compression and timing are far from "significant" unless you're using forced induction or build an engine specifically for it.

To return to what I believe is the OP's question... IMHO I don't think building an engine to specifically run pump gas E27 in Brazil is worth the time, trouble, or money. Especially when I believe the issue isn't the Ethanol percentage...It's the quality of the pump gas Brazil that's the problem. But go ahead if you want, it's your wallet.

If you want to build a drag only Harley in South Dakota to run on Methanol, go for it. Sounds like fun.